Clamping device for tool holder

ABSTRACT

A tool assembly includes a support body, a clamping device, and a tool holder clamped in a groove of the support body. A stopper block is disposed in the groove and abuts against the tool holder for positioning the tool holder along an axis. The stopper block is held in place by a wedge-type stopper clamp which applies a clamping force to the stopper block in a direction transversely of the axis. A wedge-type holder clamp is provided for applying a clamping force to the tool holder in a direction transversely of the axis. The stopper clamp is secured to the support body by a single fastening bolt, and the holder clamp is attached to the support body by a single fastening bolt. Each of the fastening bolts is provided with a part that forcefully pushes the respective clamp away from the support body in response to loosening of the fastening bolt. The arrangement is such that the tool holder can be inserted and removed without completely removing the holder clamp or its fastening bolt.

This application claims priority under 35 U.S.C. §§119 and/or 365 toPatent Application Serial No. 2002-311444 filed in Japan on Oct. 25,2002; Patent Application No. 2002-329837 filed in Japan on Nov. 13,2002; and Patent Application No. 2003-207909 filed in Japan on Aug. 19,2003. The entire contents of those applications are incorporated hereinby reference.

BACKGROUND OF THE INVENTION

The present invention relates to a clamping device for attaching a toolholder to various kinds of machine tools including a lathe, a numericalcontrolled lathe and an automatic copying lathe.

A conventional tool assembly 101 comprising a support body 102 and aplurality of tool holders 111 is depicted in FIG. 8. A clamping devicefor each tool holder 111 shown in FIG. 8 is provided with a wedge-typeholder clamping tool 112 having a plurality of fastening bolts 114 andone jack-up bolt 113. A plurality of fastening bolts of the wedge-typeholder clamping tool are fastened to the support body 102, so that thetool holder can be connected to the support body via interaction betweenrespective wedge surfaces (not shown) of the wedge-type holder clampingtool 112 and the support body, which interaction pushes the clampingtool 112 against the tool holder 111. When the tool holder is to beremoved from the clamping device, the jack-up bolt 113 that has beenloosened in advance is screwed against the support body after the pluralclamping bolts are loosened, so that the wedge surface of the wedge-typeholder clamping tool is forcefully moved away from the wedge surface ofthe support body. Thus, the tool holder can be removed.

Various kinds of devices for simplifying attachment/removal of the toolholder are well known. A device for holding a tool holder shank in amachine tool is disclosed in Japanese Unexamined Patent Publication No.2000-190110. The device releasably holds a holder shank of the toolholder to which a cutting insert is attached and a lock rod is providedon a base member. The attachment/removal structure between the holdershank and the lock rod is complicated and it is difficult to reduce thesize of the device.

Japanese Unexamined Patent Publication No. 2001-300802 discloses adetachable securing mechanism of a cutting tool used in a comb-type toolrest of a machine tool such as a numerical controlled lathe. Themechanism is provided with a supporting member for supporting anarrangement of plural tools. The supporting member attaches the cuttingtool to the comb-type tool rest of the machine tool by fastening aplurality of mounting bolts.

However, in the above conventional clamping device for a tool holder, ittakes a long time to attach/remove the tool holder because it isrequired that a plurality of clamping bolts are fastened or loosened inattachment/removal of the tool holder.

Accordingly, there is a problem in miniaturization and simplification ofthe device because the structure of the device is complicated. Inaddition, it is difficult to repeatedly and accurately set the positionof a top cutting edge because the placement of the cutting holder at apredetermined position must be visually checked.

In view of the above conventional prior art, the object of the presentinvention is to provide a clamping tool capable of reducing anattachment/removal time when one or plural tool holders, especiallysmall tool holders, are attached to or removed from the machine toolsuch as the lathe, the numerical controlled lathe and the automaticcopying lathe, and capable of improving the accuracy in positioning ofthe tool holder.

SUMMARY OF THE INVENTION

In a clamping device to which one or plural tool holders are attached,according to the present invention, the entire length of a wedge-typeholder clamping tool for fastening the tool holder to the clampingdevice is shorter than that of a conventional clamping tool, and onlyone fastening bolt is provided on the wedge-type holder clamping tool.When the one fastening bolt is loosened, the clamping tool is forcefullydisplaced away from the support body, so that the tool holder can beattached to or removed from the clamping device. Preferably, this isdone without completely removing the clamping tool or the fasteningbolt.

With this structure, in the clamping device for the tool holderaccording to the present invention, the number of the fastening boltscan be reduced and a jack-up bolt can be dispensed with, and thus aminiaturization and simplification of the wedge-type holder clampingtool can be archived. In addition, the reduction of time required forattaching/removing the tool holder to/from the clamping device can bearchived without modifying a tool holder generally and currently used.

Furthermore, in the clamping device to which the one or plural toolholders are attached, according to the present invention, the clampingdevice for the tool holder is provided with a stopper block provided atthe rear end of the tool holder remotely of a cutting edge of the toolholder, and a wedge-type stopper clamping tool is provided for securingthe stopper block to a predetermined position. Thus, the position of thetool holder can be accurately controlled when the tool holder isattached to the clamping device.

Furthermore, the wedge-type holder clamping tool according to thepresent invention is provided with a mounting bolt so that the toolholder can be attached to the clamping device with stability. Themounting bolt is replaced with an elastic mounting tool or a mountingbolt with an elastic mounting tool, so that the tool holder can beattached to the clamping device with further stability.

BRIEF DESCRIPTION OF THE DRAWINGS

The objects and advantages of the invention will become apparent fromthe following detailed description of preferred embodiments thereof inconnection with the accompanying drawings in which like numeralsdesignate like elements.

FIG. 1( a-1) shows a side view of a tool assembly according to thepresent invention, with a tool holder secured in place.

FIG. 1( a-2) is an end view of FIG. 1( a-1).

FIG. 1( b-1) is a view similar to FIG. 1( a-1) of a second embodimentaccording to the present invention.

FIG. 1( b-2) is an end view of FIG. 1( b-1).

FIG. 2( a) is a side view of a fastener bolt extending through a holderclamp and carrying an elastic ring, according to the present invention.

FIG. 2( b) is a side view of a different fastening bolt having a groovetherein for receiving an elastic ring.

FIG. 2( c) is a view similar to FIG. 2( b) with the elastic ring mountedin the fastening bolt.

FIG. 3 is a side view of a double-threaded fastening bolt according tothe present invention.

FIG. 4( a-1) is a view similar to FIG. 1( a-1) of a further embodimentaccording to the present invention.

FIG. 4( a-2) is an end view of FIG. 4( a-1).

FIG. 4( b-1) is a view similar to FIG. 1( a-1) of still anotherembodiment according to the present invention.

FIG. 4( b-2) is an end view of FIG. 4( b-1).

FIG. 4( c-1) is a view similar to FIG. 1( a-1) of still anotherembodiment according to the present invention.

FIG. 4( c-2) is an end view of FIG. 4( c-1).

FIG. 5( a-1) is a view similar to FIG. 1( a-1) of another embodimentaccording to the present invention.

FIG. 5( a-2) is a plan view of FIG. 5( a-1).

FIG. 5( a-3) is an end view of FIG. 5( a-1).

FIG. 5( b-1) is a view similar to FIG. 1( a-1) of still anotherembodiment according to the present invention.

FIG. 5( b-2) is an end view of FIG. 5( b-1).

FIG. 5( b-3) is a sectional view through FIG. 5( b-1).

FIG. 5( b-4) is an end view of FIG. 5( b-3).

FIG. 6( a-1) is a view similar to FIG. 1( a-1) of still anotherembodiment according to the present invention.

FIG. 6( a-2) is an end view of FIG. 6( a-1).

FIG. 6( b-1) is a view similar to FIG. 1( a-1) of still anotherembodiment according to the present invention.

FIG. 6( b-2) is an end view of FIG. 6( b-1).

FIG. 6( c-1) is a view similar to FIG. 1( a-1) of still anotherembodiment according to the present invention.

FIG. 6( c-2) is an end view of FIG. 6( c-1).

FIG. 7( a) is a side view of an alternative form of tool holderaccording to the present invention.

FIG. 7( b) is a plan view of FIG. 7( a).

FIG. 7( c) is an end view of FIG. 7( b).

FIG. 8 is a view of a prior art tool assembly in which a plurality oftool holders are clamped.

FIG. 9( a) is an end view of a spring plunger screw according to thepresent invention.

FIG. 9( b) is a sectional view through the spring plunger screw of FIG.9( a).

FIG. 9( c) is an opposite end view of the spring plunger screw of FIG.9( a).

FIG. 10 is a schematic perspective view of a tool assembly according toanother embodiment of the present invention wherein a fastening screw issecured by a spring nut.

FIG. 11 is a perspective view through a tool holder clamp according toanother embodiment of the invention, wherein the fastening screw issecured by a sleeve nut.

FIG. 12 is a view similar to FIG. 10, except that the tool assembly isshown from an opposite side, and a biasing spring is disposed therein.

FIG. 13 is a view similar to FIG. 12 employing a different type ofspring.

FIG. 14 is a perspective view of a tool assembly according to a furtherembodiment of the present invention.

FIG. 15 is a perspective view of a tool holder clamp according to yetanother embodiment of the present invention.

FIG. 16 is a view similar to FIG. 15 of yet another embodiment accordingto the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Depicted in FIG. 1( a-1) is a tool assembly comprising a support body1A, a tool holder 5 mounted in a groove 1B of the support body, and aclamping device for clamping the tool holder. The tool holder carries areplaceable cutting insert 5-1. In practice, there would be numeroustool holders with respective clamping devices, but only one tool holderis depicted herein. The clamping device includes a stopper block 2disposed behind the tool holder for positioning the tool holder along anaxis A, a wedge-type stopper clamping tool (stopper clamp) 3 forclamping the stopper block in place, a first fastener 6 for securing theclamping tool 3 to the support body 1A, a wedge-type holder clampingtool (holder clamp) 4 for clamping the tool holder in place, and asecond fastener 7 for securing the clamping tool 4 to the support body1A. The fastener 6 extends through a through-hole 8′ formed in thestopper clamp 3, and is secured in the support body 1A by a threadconnection. The fastener 7 is similarly attached. Thus, each fastener 6,7 has a threaded shank that can be directly threaded to the supportbody, or indirectly thereto as explained in connection with FIGS. 10–16.

With the above structure, the fastening bolts 6, 7 are rotated in afastening direction so that the wedge-type stopper clamping tool 3 andthe wedge-type holder clamping tool 4 are fastened to the support body1A, respectively, and are rotated in a loosening direction so that thewedge-type stopper clamping tool 3 and the wedge-type holder clampingtool 4 are moved away from the support body 1A, and thus the tool holdercan be detachably attached to the support body.

In the support body 1A (to which, for example, one tool holder isattached in the following embodiments) that is shown in FIGS. 1( a-1)and 1(a-2), wedge surfaces 12 a, 12 b of the tool 4 and the support body1A engage one another to force the tool 4 downwardly against the toolholder 5. Thus, a side face 13 of the wedge-type holder clamping tool 4and a side face 14 of the tool holder 5 are clamped to each other byforces directed at right angles to the axis A and to a groove bottom(abutment surface) 15 of the support body 1A. In the support body 1Ashown in FIGS. 1( b-1) and 1(b-2), the side face 13 of the wedge-typeholder clamping tool 4 is clamped, at an angle 16, to the side face 14of the tool holder 5. To this end, the side face 13 of the tool holdermust be oriented at an angle 16 shown in FIG. 1( b-2).

FIGS. 2( a), 2(b) and 2(c) show the clamping tool fastening bolt 7. Inthese drawings, only the clamping tool fastening bolt 7 is shown. Thestopper fastening bolt 6 can be formed into the same shape as that ofclamping tool fastening bolt 7. In FIG. 2( a), the clamping toolfastening bolt 7 is attached to the wedge-type holder clamping tool 4.The fastening bolt is provided with, for example, an elastic element inthe form of a ring 17 such as a lock washer or a spring washer. Theelastic ring pushes the wedge-type holder clamping tool 4 (or thestopper clamping tool 3 in the case of the fastening bolt 6) in adirection D away from the clamping device upon loosening the fasteningbolt when the wedge-type stopper clamping tool 3 or the wedge-typeholder clamping tool 4 is to be removed from the clamping device.Therefore, the wedge-type stopper clamping tool 3 or the wedge-typeholder clamping tool 4 can be attached to or removed form the clampingdevice by the use of only one fastening bolt provided with the elasticring. In order to attach the elastic ring to the fastening bolt, a slit10 can be provided in the fastening bolt as shown in FIG. 2( b) and theelastic ring is attached to the slit as shown in FIG. 2( c).

Furthermore, as shown in FIG. 3, in lieu of using an elastic ring 17,there can be used a fastening bolt 7′ with left and right-hand screwthreads, i.e., a left-hand thread 7′-1 and right-hand thread 7′-2. Whenfastening bolts with the left and right-hand screws are used, the boltthrough holes 8′, 9′ in the wedge-type stopper clamping tool 3 and thewedge-type holder clamping tool 4 are replaced with threaded holeshaving the same pitch as that of the corresponding thread of thecorresponding thread of the fastening bolts. For example, the left-handthread is used for the threaded holes of the wedge-type holder clampingtools 3, 4 because the right-hand thread is used for the threaded holesof a conventional clamping device 1 (for example, a tool rest includingan automatic copying lathe). Accordingly, for example, when the toolholder 5 is attached, the fastening bolt 7′ with the left and right-handscrews is rotated in an attaching direction, so that the wedge-typeholder clamping tool 4 is moved in a direction to clamp the tool holder5, so as to clamp the tool holder 5 to the support body 1A. On the otherhand, the fastening bolt 7′ with the left and right-hand screws isrotated in a removing direction, so that the wedge-type holder clampingtool 4 is positively moved away from the tool holder 5 so as to removethe tool holder 5 from the support body 1A. Similar to the above, whenthe stopper block 2 is secured by the wedge-type stopper clamping tool3, the block can be attached or removed by use of fastening bolt 6 withthe left and right-hand screws. Thus, the wedge-type stopper clampingtool 3 or the wedge-type holder clamping tool 4 can be attached to orremoved from the clamping device by use of only the fastening bolt withthe left and right-hand screws. It will be appreciated that the devicecan be made smaller because the fastening bolt has no portion whosediameter is larger than the diameter of the threaded portions. Namelythe clamping device can be applied to a tool holder having a smallshaft.

The wedge-type holder clamping tool for attaching the tool holder to theclamping device with stability will be described below. In order toattach the tool holder to the clamping device with further stability, asshown in FIGS. 4( a-1) to 4(c-2), the wedge-type holder clamping tool 4is provided with pressing bolts 18-1, 18-2, 18-3 for pressing againstthe side face 14, a top face or a corner 19 of the tool holder 5. FIGS.4( a-1) to 4(b-2) show the pressing bolt for pressing against the sideface 14. FIGS. 4( c-1) and 4(c-2) shows the pressing bolt for pressingagainst the corner 19. As described above, the wedge-type holderclamping tool is provided with the pressing bolt so that the tool holdercan be appropriately attached to the side face and the bottom face ofthe groove of the clamping device with stability.

In order to further accurately position the tool holder 5 in the axialdirection thereof, according to the present invention, the stopper block2 can be provided with an adjusting bolt 20 or a positioning bar 23 asadjusting means, as shown in FIGS. 5( a-1) to 5(b-4). As shown in FIG.5( a-1), the first adjusting bolt 20 extends through the stopper block 2along the central axis thereof, and has a maximum length that is largerthan the maximum length of the stopper block. The end face of theadjusting bolt that is in contact with the rear end of the tool holderhas a diameter smaller than that of the adjusting bolt. The firstadjusting bolt 20 positions the stopper block at a predeterminedposition by use of the wedge-type stopper clamping tool 3. The adjustingbolt 20 provided in the stopper block 2 positions the tool holder at apredetermined position. As shown in FIG. 5( b-3), the second positioningbar 23 is inserted into a hole that extends through the stopper block 2along the central axis thereof. The positioning bar 23 is secured andpositioned by a securing bolt 21 and a positioning screw 22 that areengaged in threaded holes provided in one face of the stopper block. Thesecond positioning bar 23 positions the stopper block at a predeterminedposition by use of the wedge-type stopper clamping tool 3. As shown inFIG. 5( b-3), the chamfered end of the positioning bar 23 on the side ofthe bar that faces the tool holder is pressed against the tool holder toposition the tool holder by use of the positioning screw 22 provided inthe stopper block 2. After that, the positioning bar 23 is secured bythe securing bolt 21. This enables the tool holder to be extremelyaccurately positioned at a predetermined position.

Another means for positioning the tool holder 5 in the axial directionthereof will be described below. As shown in FIGS. 6( a-1) to 6(c-2),V-shaped cuts or recesses 24 are provided at a longitudinal corner ofthe tool holder 5. In addition, the wedge-type holder clamping tool isprovided with at least one pressing bolt 18-1 (in FIGS. 6( a-1)(a-2)),pressing bolt 18-2 (in FIGS. 6( b-1) (b-2)), and pressing bolt 18-3 (inFIGS. 6( c-1)(c-2)). At least one pressing bolt 18-1, 18-2, 18-3 ispressed against an inclined surface (near the stopper block) of theV-shaped cut 24, so that the tool holder 5 can be pressed against thestopper block 2 at a predetermined pressure. The pressing bolt 18-1 isengaged toward the side face of the clamping device; the pressing bolt18-2 is engaged toward the bottom face of the groove of the clampingdevice; and the pressing bolt 18-3 is engaged at a predetermined anglewith respect to the side face and the bottom face of the groove of theclamping device. By means of any of the pressing bolts, the tool holdercan be pressed against the side face and the bottom face of the grooveof the clamping device. The top end of the pressing bolt 18-1, 18-2,18-3 is shaped into a hemisphere or a cone corresponding to the V-shapedcut. However, if no cut is provided, the top end can be flat.

The wedge-type holder clamping tool that attaches the tool holder to theclamping device with further stability will be described below. In orderto attach the tool holder to the clamping device with further stability,the wedge-type holder clamping tool 4 is provided with the elasticpressing tool or the pressing bolt with the elastic pressing tool inplace of the pressing bolts shown in FIGS. 6( a-1) to 6(c-2). Also, theelastic pressing tool or the pressing bolt with the elastic pressingtool is pressed against the side face 14, the top face or the corner 19of the tool holder 5. As described above, the wedge-type holder clampingtool is provided with the elastic pressing tool or the pressing boltwith the elastic pressing tool, so that the tool holder can beappropriately attached to the side face and the bottom face of thegroove of the clamping device with stability. A spring coil, an elasticrubber, a plate spring, a spring washer, a coned disc spring, a springplunger screw or the like is used as the elastic pressing tool and inthe pressing bolt with the elastic pressing tool. As an example of theelastic pressing tool and the pressing bolt with the elastic pressingtool, a spring plunger screw is shown in FIGS. 9( a–c). The springplunger screw 26 is provided with: (i) a screw portion 26-1 that pressesthe tool holder against the abutment surfaces of the groove 1B, (ii) atop end (having a round or flat end) 26-2 that abuts with the toolholder, (iii) a plug screw 26-3 that secures a spring, and (iv) a spring26-4 that presses the tool holder via the top end thereof.

Means for positioning the tool holder 5 in the axial direction thereofby using the elastic pressing tool or the pressing bolt with the elasticpressing tool in place of the above pressing bolts will be describedbelow. In such means, the V-shaped cuts 24 are provided at alongitudinal corner of the tool holder 5 shown in FIGS. 6( a-1) to6(c-2), and the wedge-type holder clamping tool is provided with atleast one pressing bolt with the elastic pressing tool (for example, thespring plunger screw in FIGS. 9 a-c) in place of the pressing boltsshown in FIGS. 6( a-1) to 6(c-2). In such means, at least one pressingbolt with the elastic pressing tool is pressed against such an inclinedsurface (near the stopper block) of the V-shaped cut 24, so that thetool holder 5 can be pressed against the stopper block 2 at apredetermined pressure. The pressing bolt with the elastic pressing toolused in place of the pressing bolt shown in FIGS. 6( a-1)(a-2) isengaged toward the side face of the clamping device; the pressing boltwith the elastic pressing tool used in place of the pressing bolt shownin FIGS. 6( b-1)(b-2) is engaged toward the bottom face of the groove ofthe clamping device; and the pressing bolt with the elastic pressingtool used in place of the pressing bolt shown in FIGS. 6( c-1)(c-2) isengaged at a predetermined angle with respect to the side face and thebottom face of the groove of the clamping device. By means of any of thepressing bolts with the elastic pressing tool (e.g., a spring plungerscrew, a spring coil, an elastic rubber, a plate spring, a springwasher, a coned disc spring or the like), the tool holder can be pressedagainst the side face and the bottom face of the groove of the clampingdevice. The top end of the elastic pressing tool that abuts with theV-shaped cut 24 is shaped into a hemisphere or a cone corresponding tothe V-shaped cut. However, if no cut is provided, the top end can beflat.

Furthermore, in the present invention, the attaching efficiency and thepositioning of the tool holder 5 can be further improved by modifying apart of the tool holder 5. As shown in FIGS. 7( a–c), in order toimprove the attaching efficiency of the tool holder 5, a chamfer 25(e.g., a back taper, a truncated cone shape, spherical shape or pluralcombinations of the back taper, a truncated cone shape and a sphericalshape) is provided on the rear end of the tool holder, so that the toolholder can be easily attached to the support body 1A.

Furthermore, in the clamping device according to the present invention,a conventional long tool holder can be attached in place of the stopperblock 2, by using both the wedge-type stopper clamping tool 3 and thewedge-type holder clamping tool 4.

The holder clamping tool 4 can be held in place as shown in FIGS. 10 and11. As shown in FIG. 10, in the clamping device of the tool holderaccording to the present invention, the fastening bolt 7 of thewedge-type holder clamping tool 4 is attached to a spring nut 121 todefine a thread connection. The spring nut 121 prevents the clampingtool fastening bolt 7 from being detached from the wedge-type holderclamping tool 4, and the wedge-type holder clamping tool 4 is heldbetween the nut 121 and a head of the bolt 7.

As shown in FIG. 11, in the clamping device of the tool holder accordingto the present invention, the fastening bolt 7 of the wedge-type holderclamping tool 4 is fastened to a threaded sleeve-type nut 122 to definea thread connection. Rotation of the nut 122 is facilitated by a knurledring 123.

In each of FIGS. 10 and 11, the holder clamping tool 4 has a slot 9″elongated in a direction transversely of the axis A and through whichthe bolt 7 passes. As a result, by loosening the bolt 7 and slightlydisplacing the holder clamping tool 4 out of the groove 1B, the clampingtool 4 can be raised away from the tool holder in order to allow removal(or insertion) of the tool holder even while the fastening bolt 7remains secured in the support body 1A. Thus, with any structure havingthe feature described with reference to FIGS. 10 and 11, the tool holder4 can be temporarily fastened without completely detaching the clampingtool fastening bolt 7 or the holder clamp 4.

Other types of wedge-type holder clamping tools 4 which can temporarilyfasten the tool holder 5 without fully detaching the clamping tool 4 orthe fastening bolt 7 will be described below with reference to FIGS. 12to 16, wherein a spring is provided which presses the holder clamp 4against the tool holder 5 to hold the latter in place.

As shown in FIG. 12, in the clamping device of the tool holder accordingto the present invention, the fastening bolt 7 is fastened to the springnut 121. An upwardly extending spring mounting slit 127 is provided inthe holder clamp 4 to one side of the elongated through hole 9″ of thewedge-type holder clamping tool 4. A biasing spring 126 extends into theslit so that a spring end 126-1 exerts an elastic biasing force in adirection to increase a distance between the clamping device and awedge-type side face 12 a of the wedge-type holder clamping tool 4, sothat the holder clamping tool 4 presses against the holder 5. Thus, thetool holder 5 remains temporarily fastened to the support body 1A evenwhile the clamping bolt fastening tool 7 is loosened but still securedto the support body 1A. In that state, the tool holder 5 can be insertedor removed.

As shown in FIG. 13, the biasing spring 128 has an end 128-1 whichexerts the elastic biasing force described above.

As shown in FIG. 14, the fastening bolt 7 is fastened to the sleeve nut122. A leaf spring 124 is provided in the wedge-type holder clampingtool 4 between the sleeve nut 122 and a wedge-type side face 12 a of thewedge-type holder clamping tool to temporarily fasten the tool holder 5to the clamping device. Accordingly, the leaf spring 124 exerts anelastic force in a direction to increase a distance between thewedge-type side face 12 a and the sleeve nut 122. Thus, the holderclamping tool 4 presses against the tool holder 5, wherein the toolholder 5 remains temporarily fastened to the clamping device, even whenthe clamping bolt fastening tool 7 is loosened.

As shown in FIG. 15, a coil spring 125 having a fixed end is provided inplace of the leaf spring 124. Accordingly, the coil spring 125 having afixed end exerts an elastic force in a direction to increase a distancebetween the wedge-type side face 12 a and the sleeve nut 122, so thatthe tool holder 5 is temporarily fastened to the clamping device, whenthe clamping bolt fastening tool 7 is loosened.

As shown in FIG. 16, the wedge-type holder clamping tool 4 is providedwith the sleeve nut 122. A laterally biasing spring mounting slit 131 isprovided in one of opposite side surface portions of the bolt throughhole 9″ of the wedge-type holder clamping tool 4 in the minor axisdirection thereof. A laterally biasing spring 129 is mounted in thelaterally biasing spring mounting slit. One end of the laterally biasingspring 129 is inserted into a hole 132 of the laterally biasing springmounting slit, and the other end of the laterally biasing spring 129 isdisposed between the clamping device fastening bolt 7 and the wedge-typeside face 12 a. With this structure, the laterally biasing spring 129exerts an elastic force in a direction to increase a distance betweenthe wedge-type side face 12 a and the sleeve nut 122, so that the toolholder 5 is temporarily fastened to the clamping device 1, when the bolt7 is loosened.

Therefore, with any structure described with reference to FIGS. 12 to16, the tool holder 5 can be temporarily fastened without detaching theclamping device fastening bolt 7 from the wedge-type holder clampingtool 4. The tool holder 5 can also be inserted and detached from thesupport body 1A with the bolt 7 being loosened. Moreover, the featuresdisclosed in connection with FIGS. 10–16 can be employed in conjunctionwith a part which pushes the clamp in a direction away from the groove13 upon loosening the bolt 7, such as the elastic ring 17.

EFFECT OF THE INVENTION

In the clamping device for the tool holder according to the presentinvention, the number of fastening bolts for the tool holder can bereduced; the jack-up screws can be dispensed with; and a miniaturizationand the simplification of the wedge-type holder clamping tool can beachieved. Thus, the time required for attachment/removal of the toolholder can be reduced without modifying the tool holder and the clampingdevice for the tool holder that are currently used.

Furthermore, in the clamping device for the tool holder according to thepresent invention, the tool holder can be disposed at an accurateposition, and can be repeatedly disposed at the same accurate positioneven when replaced. Also, in the clamping device for the tool holderaccording to the present invention, the tool holder can be temporarilyfastened without being detached from the clamping device and withoutdetaching the clamping tool fastening bolt from the wedge-type holderclamping tool when the tool holder is attached to and detached from theclamping device.

Although the present invention has been described in connection withpreferred embodiments thereof, it will be appreciated by those skilledin the art that additions, deletions, modifications, and substitutionsnot specifically described may be made without departing from the spiritand scope of the invention as defined in the appended claims.

1. A tool assembly comprising a support body, a clamping device, and atool holder clamped in the support body by the clamping device; thesupport body including a groove in which the tool holder is disposed,the groove including an abutment surface arrangement against which thetool holder abuts, the clamping device including: a stopper blockmounted in the groove and abutting against the tool holder, forpositioning the tool holder along an axis; a stopper clamp including: afirst wedge portion wedged in the groove and arranged to press againstthe stopper block in a direction transversely of the axis, and a firstmounting portion having a first through-hole; a first fastener includinga first shank extending through the first through-hole and including afirst thread portion threadedly secured to the support body by a firstthread connection to fasten the stopper clamp to the support body, thefirst fastener including a stopper clamp-displacing part for displacingthe stopper clamp away from the support body in response to unscrewingof the first fastener; a holder clamp including: a second wedge portionwedged in the groove and arranged to press against the tool holder in adirection transversely of the axis, and a second mounting portion havinga second through-hole; and a second fastener including a shank extendingthrough the second through-hole and including a second thread portionsecured to the support body by a second threaded connection to fastenthe holder clamp to the support body, the second fastener including aholder clamp displacing part for displacing the holder clamp away fromthe support body in response to unscrewing of the second fastener. 2.The tool assembly according to claim 1 wherein each of the first andsecond fasteners includes a head joined to the shank, wherein each ofthe clamp-displacing part and the holder clamp-displacing part comprisesan elastic element situated between the head and the respective stopperclamp and holder clamp.
 3. The tool assembly according to claim 2wherein the elastic element comprises a ring mounted on the shank. 4.The tool assembly according to claim 1 wherein each of the first andsecond shanks includes both a right-hand thread and a left-hand thread,wherein one of the right- and left-hand threads of the first shank isthredely connected to the first through-hole and constitutes the stopperclamp-displacing part thereof, and one of the right- and left- handthreads of the second shank is threadedly connected to the secondthrough-hole and constitutes the holder clamp-displacing part thereof.5. The tool assembly according to claim 1 wherein the holder clampcarries an adjustable pressing bolt arranged to press against a portionof the tool holder.
 6. The tool assembly according to claim 5 whereinthe tool holder includes a generally V-shaped recess for receiving thepressing bolt.
 7. The tool assembly according to claim 1 wherein thestopper block carries an adjusting member engageable with the toolholder for adjusting a position of the tool holder along the axis. 8.The tool assembly according to claim 7 wherein the adjusting membercomprises a threaded bolt.
 9. The tool assembly according to claim 7wherein the adjusting member comprises a slidable positioning bar, and athreaded positioning bolt engageable with the positioning bar foradjusting a position of the positioning bar.
 10. The tool assemblyaccording to claim 1 further including a spring nut in which the secondthread portion is secured, to define the second threaded connection, thesecond fastener including a head joined to the shank thereof; the holderclamp being secured between the head and the spring nut.
 11. The toolassembly according to claim 10 further including a sleeve nut in whichthe second thread portion is secured, to define the second threadedconnection, the second fastener including a head joined to the shankthereof; the holder clamp being secured between the head and the sleevenut.
 12. The tool assembly according to claim 1 further including aspring arranged to yieldably press the holder clamp against the toolholder.
 13. The tool assembly according to claim 12 wherein the secondthrough-hole is elongated in a direction enabling the holder clamp tomove relative to the second fastener and away from the tool holder whenthe second fastener is loosened.
 14. The tool assembly according toclaim 12 wherein the spring extends into a slit formed in the holderclamp.
 15. The tool assembly according to claim 12 wherein the springcomprises a leaf spring.
 16. The tool assembly according to claim 1wherein the first fastener constitutes the only fastener securing thestopper clamp to the support body, and the second fastener constitutesthe only fastener securing the holder clamp to the support body.